This invention concerns an iron club head and, more specifically, it relates to an iron club head in which at least the ball hitting region of the head main body is formed with fiber-reinforced synthetic resin material.
The iron club heads have generally been formed integrally from metal material such as soft iron or stainless steel in the shape and weight according to respective club number. However, since the club heads of this kind are in the form of a metal block, such are poor in resiliency, especially lacking in resiliency at the hitting face, which is most important for hitting a ball. The repellent coefficient is small and thus inadequate to obtain a soft feeling upon hitting, as in the case of a wood club, whereby the impact shock upon hitting is transmitted to the grip and with an unsatisfactory ball flight distance being obtained.
In view of the above, at least the face (hitting face) portion of the club head main body is formed with fiber-reinforced synthetic resin material incorporated with carbon fibers or the like thereby improving the repellent force at the hitting face and causing a soft feeling upon hitting a ball, as disclosed, for example, in Japanese Utility Model Laid-Open Publication No. 16670/1984 in which a metal main body comprising a plate-like core member erected, for example, about at the middle of a sole portion in continuity with the shaft inserting portion (hosel) in the longitudinal direction of the sole portion and an outer synthetic resin member is integrally molded to the main body; or as disclosed in Japanese Patent Utility Model Laid-Open Publication No. 190270/1984 in which a core portion substantially of a trigonal cross section protruding integrally from the sole portion at the lower end of a golf club head upwardly is made of metal, such as soft iron or stainless steel. A plurality of through holes penetrating the core portion in the forward and backward directions are provided and the fiber-reinforced synthetic resin mainly composed of carbon fibers is integrally covered to harden approximately in an inverted adversed V-shape at the front and rearward face of the core, while the fiber-reinforced synthetic resin is filled in in each of the holes.
However, although a plurality of perforations are disposed in each of the known examples, the main purpose thereof resides in enhancing the securement between the synthetic resin and the metal member but not in intending the enlargement for the sweet spot. Further, in the conventional club in which the entire head is made only with metal, since the hosel portion is in a long cylindrical shape so as to provide thick and effective joining area in view of the joining strength with the shaft and the weight is localized toward the heel side, it has been difficult to arrange the sweet spot at the center of the ball hitting region. Moreover, in those clubs of the type in the foregoing two citations in which the ball hitting region is covered with a synthetic resin of a low specific gravity, the sweet spot is further localized toward the heel side and the sweet spot is missed even when the ball is hit at the appropriate central position of the hitting face, thereby reducing the ball flight distance.
This invention has been made in order to overcome the foregoing problems in the prior art and one object thereof is to properly disperse the weight of the ball hitting region in all directions, thereby makng the sweet spot position appropriate and enlarging the sweet spot through the spaces between the sole and hosel portions and the ball hitting region which is thickest in the metal body.
Another object of this invention is to provide an iron club head capable of facilitating the shaping of the ball hitting region made of synthetic resin and weight setting and having high joining strength, without reducing the repellent force and the feeling upon hitting the ball.